Mathematically determine the precision and scale of a decimal value

Question

I have been looking at some way to determine the scale and precision of a decimal in C#, which led me to several SO questions, yet none of them seem to have correct answers,

Answer 1

Racil's answer gives you the value of the internal scale value of the decimal which is correct, although if the internal representation ever changes it'll be interesting.

In the current format the precision portion of decimal is fixed at 96 bits, which is between 28 and 29 decimal digits depending on the number. All .NET decimal values share this precision. Since this is constant there's no internal value you can use to determine it.

What you're apparently after though is the number of digits, which we can easily determine from the string representation. We can also get the scale at the same time or at least using the same method.

public struct DecimalInfo
{
    public int Scale;
    public int Length;

    public override string ToString()
    {
        return string.Format("Scale={0}, Length={1}", Scale, Length);
    }
}

public static class Extensions
{
    public static DecimalInfo GetInfo(this decimal value)
    {
        string decStr = value.ToString().Replace("-", "");
        int decpos = decStr.IndexOf(".");
        int length = decStr.Length - (decpos < 0 ? 0 : 1);
        int scale = decpos < 0 ? 0 : length - decpos;
        return new DecimalInfo { Scale = scale, Length = length };
    }
}